Victoria Police say they have credible information regarding the threat of violence in an escalating feud between the Bandidos and the Hells Angels outlaw motorcycle gangs.
Tensions were fuelled on Friday night after more than 30 shots were fired at a man who is believed to be Bandidos enforcer Toby Mitchell.
Mitchell was seriously injured in another shooting in 2011 at Brunswick.
Police are describing the threat as very real and Assistant Commissioner Stephen Fontana says they will crack down hard on any outbreaks of violence.
"When you've got public shootings like last Friday night, with over 30 shots and other activity, the threat is real," he said.
"The thing that concerns us [is if] it plays out in the public arena.
"We have concerns about a feud that is escalating and we're warning our members to take care. We don't want anyone getting hurt."
Assistant Commissioner Fontana says it is an unpredictable situation.
"We're concerned about violence, retaliation - a whole range of things - and we don't know how it will play out," he said.
"[It] could result in abductions. That's a common thing amongst them - where they might abduct people ... some of the other members off the streets.
"Murder, torture, a whole range of things could happen with these people."
Victoria Police are working with the Australian Crime Commission and Federal Police on the operation.